A method of forming a threaded bore in a compression molded part comprises: positioning at least one rotatable threaded shaft in a mold cavity during compression molding of a part; rotatably driving the at least one threaded shaft for unthreading the at least one threaded shaft from the part; and pushing the at least one threaded shaft away from the mold cavity once the at least one threaded shaft is unthreaded from the part.

An access port member includes: a body 8 to be connected to a predetermined portion of a blood circuit for causing a patient's blood to extracorporeally circulate, the body 8 internally including a flow path 8b for circulating the blood and having an opening 8c communicating with the flow path 8b; a valve 9 that is made of an elastic member covering the opening 8c and attached to an attachment part 8d of the body 8, the valve including a slit that makes a transition from a closed state to an open state when pressed by a tip 11a of a syringe 11 capable of collecting blood or injecting a drug; a cap part 10 fixed to the body 8 with the valve portion 9 interposed therebetween and the slit 9a facing outward; and a rib 9b formed integrally along the periphery of the slit 9a in the valve 9.

A method of forming a threaded bore in a compression molded part comprises: positioning at least one rotatable threaded shaft in a mold cavity during compression molding of a part; rotatably driving the at least one threaded shaft for unthreading the at least one threaded shaft from the part; and pushing the at least one threaded shaft away from the mold cavity once the at least one threaded shaft is unthreaded from the part.

A thread forming device for compression molding comprises a base positioned adjacent a compression molding device, a plurality of posts extending from the base, a carrier moveable along the posts and supporting at least one rotatable threaded shaft, each shaft being configured for forming a threaded bore during compression molding of a part, an assembly for rotatably driving the at least one threaded shaft for unthreading the at least one threaded shaft from the part, and one or more biasing members configured to push the carrier away from the base once the at least one threaded shaft is unthreaded from the part.

An impeller in which a plurality of vanes are provided so as to overlap each other back and forth as viewed in the direction of axis has a first impeller part on a front side and a second impeller part on a rear side. A method for manufacturing impeller includes a step of molding a first impeller part, a step of molding a second impeller part and a step of combining together the first impeller part and the second impeller part.